I'm in the camp of use the center, and surrounds for home theater. Way back in the day, I started with just to channel for movies, and TV. I can't say I didn't enjoy it, I did. Very much back then. Mitches comment about planes flying past is exactly right. There are so many things going on in movies that only having two speakers will limit the experience.
I built a new from the ground up about 6 years ago. (119" screen, and Sony PJ) Regardles of what you do speaker wise, here are a couple things I would suggest.
I assume you will be using a PJ. I ran 3" PVC, 2" would work, from behind my equipment rack, (it's buried in the wall of course) up to where my PJ is mounted. When you make corners, don't use 90 degree elbows. It's better to use 2 45 degree elbows. It makes pulling wire through alot easier. Always pull an extra wire through so if you want to change, or add, you have an easy way to do it. If you use it to pull something new in, pull another extra one through. (since you will be pulling your spare out with the new one)
Even if you go the two channel route, run speaker wires to the back of your room. Just put a blank cover plate on the openings, and forget it's there. The last thing you want is to decide you would like to try the surround later and not have the wires in place. Speaker wire is cheap enough, don't limit your options. I've done some retro installs, and it's a real pain running wires through the attic, or basement, and trying to end up in the walls later. Try to cover any possible future changes now.
